package com.ruochen.gateway;

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.MultiValueMap;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

/**
 * 全局过滤器与default-filter的区别在于全局过滤器可以自己写代码
 * 基于webFlux api
 */
// 过滤器执行顺序，越小优先级越高
// @Order(-1)
@Component
public class AuthorizeFilter implements GlobalFilter, Ordered {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        // 1. 获取请求参数
        ServerHttpRequest request = exchange.getRequest();
        MultiValueMap<String, String> params = request.getQueryParams();
        // 2. 获取参数中的 authorization 参数
        String auth = params.getFirst("authorization");
        // 3. 判断参数值是否等于admin
        if ("admin".equals(auth)) {
            // 4. 是，放行
            return chain.filter(exchange);
        }
        // 5. 否，拦截
        // 5.1 设置状态码
        exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);
        // 5.2 拦截请求
        return exchange.getResponse().setComplete();
    }

    /**
     * 效果等同于注解
     *
     * @return 过滤器执行优先级
     */
    @Override
    public int getOrder() {
        return -1;
    }
}
